Search PubMed⌕ Search

Biomedical subjects

S Shimizu

Publications and source records attributed to S Shimizu.

At least 181 records · Page 10Linked to original sources
PubMed2000

Survey on antibody against parapoxvirus among cattle in Japan.

A seroepidemiological survey was performed on antibody against parapoxvirus among cattle in Japan using the agar gel immunodiffusion test and enzyme-linked immunosorbent assay. A total 1,819 sera were collected from cattle in various parts of Japan for the survey. The positive rates were in the range of 40 to 98%, and the reactors increased gradually in number with advancing age. These results indicate that parapoxvirus infection is already prevalent among cattle in Japan. It remains to be elucidated, however, whether the antibodies detected have been produced by infection of the same virus or other viruses that belong to the genus parapoxvirus.

Animals↗
PubMed2000

Sensitive enzyme-linked immunosorbent assays for the detection of bacterial superantigens and antibodies against them in human plasma.

Enzyme-linked immunosorbent assays for the quantitation of bacterial superantigens, staphylococcal enterotoxins A, B and C, toxic-shock syndrome toxin-1 and streptococcal pyrogenic exotoxin A, were developed. The assays had sensitivity to quantitate these toxins to 1.4, 5.9, 16.3, 2.5 and 4.3 pg/ml, respectively, in a buffer including 50% human plasma. It takes only 150 min to complete the assays after plate preparation. Specificity of the assays agreed with those of reverse latex agglutination assay. We also developed enzyme-linked immunosorbent assays to detect antibodies against these five superantigens. The assays are expected to be significant tools for the study of superantigens in several diseases.

Animals↗
PubMed2000

Protection against malignant progression of spontaneously developing liver tumors in transgenic mice expressing O(6)-methylguanine-DNA methyltransferase.

To study the effect of O(6)-methylguanine-DNA methyltransferase (MGMT) on carcinogenesis, we have previously generated MGMT transgenic mice overexpressing the bacterial MGMT gene, ada, and demonstrated that high MGMT levels in the liver suppress induction of liver tumors after treatment with an alkylating hepatocarcinogen. To examine the effects of life-long elevation of MGMT activity on mouse spontaneous liver tumor development, ada-transgenic and control non-transgenic mice were compared. We also examined mutations at codon 61 of the H-ras oncogene, reported as a hot spot in mouse liver tumors, using a direct DNA sequencing method. The results revealed no significant difference in tumor incidence or mutation spectrum, but interestingly, ada-transgenic mice were found to have fewer malignant tumors and survived longer, indicating a possible protective role of MGMT against malignant conversion.

Animals↗
PubMed2000

Nuclear localization of immunoreactive beta-catenin is specific to familial adenomatous polyposis in papillary thyroid carcinoma.

Thyroid carcinoma is the first symptom in some patients with familial adenomatous polyposis (FAP). We evaluated the cellular localization of beta-catenin in thyroid carcinomas associated (n = 4) or not associated (n = 173) with FAP, since loss of functional protein of the adenomatous polyposis coli (APC) gene leads to nuclear accumulation of beta-catenin in adenomas and carcinomas of the FAP colon. Immunoreactive beta-catenin was demonstrated at the cell membrane of glandular cells of the non-neoplastic thyroid and non-FAP carcinomas. On the other hand, cytoplasmic and nuclear accumulation of beta-catenin is specific to FAP-associated papillary carcinomas. The abnormality in the APC / beta-catenin pathway is thus also important in FAP-associated thyroid carcinoma, and beta-catenin immunohistochemistry is a feasible screening method to identify occult FAP in young patients with thyroid tumors.

Adenomatous Polyposis Coli↗
PubMed2000

In vivo and in vitro interactions between human colon carcinoma cells and hepatic stellate cells.

Stromal reaction is important for the growth of cancer both in primary and metastatic sites. To demonstrate this reaction during the hepatic metastasis of human colon carcinoma, we histologically investigated alterations to the distribution and phenotype of hepatic stellate cells (HSCs), the only mesenchymal cells in the liver parenchyma, using a nude mouse model. Intrasplenically injected colon carcinoma LM-H3 cells migrated into the space of Disse and underwent proliferation, in close association with hepatocytes and HSCs, at 2 days. At 14 days, HSCs were accumulated around the tumor mass and expressed alpha-smooth muscle actin, a marker for HSC activation. We next investigated in vitro the growth factors involved in the interactions between LM-H3 cells and HSCs. Conditioned medium of rat HSCs which underwent culture-induced activation contained platelet-derived growth factor (PDGF)-AB, hepatocyte growth factor (HGF) and transforming growth factor (TGF)-beta, and could augment LM-H3-cell proliferation and migration. Neutralizing antibodies against PDGF-AA and PDGF-BB and those against PDGF-BB and HGF inhibited proliferation and migration, respectively, of LM-H3 cells, whereas antibody against TGF-beta had no effect. LM-H3 cells expressed PDGF receptors-alpha and -beta and c-met. Conditioned medium of LM-H3 cells contained PDGF-AB, and could enhance HSC proliferation and migration. This augmenting effect was suppressed by treatment with anti-PDGF-AB antibody. The present study has demonstrated that bidirectional interactions involving PDGF and HGF take place in vitro between colon carcinoma cells and HSCs, raising the possibility that similar interactions might be involved in the stromal reaction during hepatic metastasis.

Adenocarcinoma↗
PubMed2000

A novel amidase (half-amidase) for half-amide hydrolysis involved in the bacterial metabolism of cyclic imides.

A novel amidase involved in bacterial cyclic imide metabolism was purified from Blastobacter sp. strain A17p-4. The enzyme physiologically functions in the second step of cyclic imide degradation, i.e., the hydrolysis of monoamidated dicarboxylates (half-amides) to dicarboxylates and ammonia. Enzyme production was enhanced by cyclic imides such as succinimide and glutarimide but not by amide compounds which are conventional substrates and inducers of known amidases. The purified amidase showed high catalytic efficiency toward half-amides such as succinamic acid (K(m) = 6.2 mM; k(cat) = 5.76 s(-1)) and glutaramic acid (K(m) = 2.8 mM; k(cat) = 2.23 s(-1)). However, the substrates of known amidases such as short-chain (C(2) to C(4)) aliphatic amides, long-chain (above C(16)) aliphatic amides, amino acid amides, aliphatic diamides, alpha-keto acid amides, N-carbamoyl amino acids, and aliphatic ureides were not substrates for the enzyme. Based on its high specificity toward half-amides, the enzyme was named half-amidase. This half-amidase exists as a monomer with an M(r) of 48,000 and was strongly inhibited by heavy metal ions and sulfhydryl reagents.

Alphaproteobacteria↗
PubMed2000

Thrombin stimulates the expression of PDGF in lung epithelial cells.

Several growth factors, including platelet-derived growth factor (PDGF), have been implicated in the mechanism of lung and airway remodeling. In the present study, we evaluated whether thrombin may promote lung and airway remodeling by increasing PDGF production from lung and airway epithelial cells. Conditioned medium (CM) was prepared by treating epithelial cells with increasing concentrations of thrombin; before use in the assays, CM was treated with hirudin until complete inhibition of thrombin activity. CM from epithelial cells stimulated the proliferation of lung fibroblasts and bronchial smooth muscle cells. Anti-PDGF antibody significantly inhibited this CM proliferative activity, implicating PDGF in this effect. Enzyme immunoassay and RT-PCR demonstrated that thrombin induced the secretion and expression of PDGF from bronchial and alveolar epithelial cells. RT-PCR showed that epithelial cells express the thrombin receptors protease-activated receptor (PAR)-1, PAR-3, and PAR-4. The PAR-1 agonist peptide was also found to induce PDGF secretion from epithelial cells, suggesting that the cellular effect of thrombin occurs via a PAR-1-mediated mechanism. Overall, this study showed for the first time that thrombin may play an important role in the process of lung and airway remodeling by stimulating the expression of PDGF via its cellular receptor, PAR-1.

Antibodies↗
PubMed2000

Tropical-wood-induced bullous erythema multiforme.

We report a case of bullous erythema multiforme caused by an exotic wood, pao ferro (Machaerium scleroxylon). A 25-year-old female, a luthier (guitar maker) who often handles a variety of woods, developed bullous erythema multiforme. A patch test confirmed a positive reaction to one of the exotic woods, pao ferro. A subsequent accidental short contact with pao ferro 5 months following the first incidence induced a similar exudative erythema. Exotic woods such as pao ferro should be added to the list of contact allergens that can induce bullous erythema multiforme.

Adult↗
PubMed2000

Mucocutaneous manifestations in Japanese HIV-positive hemophiliacs.

BACKGROUND: Although various mucocutaneous manifestations have been reported in patients infected with HIV by sexual transmission or intravenous drug use, the prevalence and characteristics of skin disorders in HIV-positive hemophiliacs coinfected with hepatitis C virus (HCV) have rarely been described. OBJECTIVE: The purpose of this study was to clarify the characteristics of skin disorders in HIV-positive hemophiliacs and to identify differences in comparison with other HIV-positive groups. METHODS: A prospective study of the prevalence of mucocutaneous manifestations in 110 Japanese hemophiliacs (53 HIV-positive hemophiliacs including 24 AIDS and 57 HIV-negative hemophiliacs) was performed from July 1997 to July 1998. RESULT: None of the hemophiliacs developed Kaposi's sarcoma or sexually transmitted skin diseases. Eosinophilic folliculitis was observed in 3 AIDS patients. The incidence of folliculitis, common warts, seborrheic dermatitis, generalized eczema, oral candidiasis and herpes zoster was higher in HIV-positive than in HIV-negative hemophiliacs (p < 0.05). Although anti-HCV antibody was positive in all HIV-positive hemophiliacs, HCV-related dermatoses such as lichen planus and porphyria cutanea tarda were not observed. CONCLUSION: Although Kaposi's sarcoma and sexually transmitted skin diseases such as molluscum contagiosum, condyloma, and scabies are frequently associated with HIV, they were not found in the HIV-positive hemophiliacs in our study. HIV infection-related mucocutaneous manifestations are influenced not only by the presence of HIV but also by other factors such as the mode of transmission and sexual habit.

Adolescent↗
PubMed2000

Purification and characterization of a novel lactonohydrolase from Agrobacterium tumefaciens.

A novel lactonohydrolase, catalyzing the stereospecific hydrolysis of L-pantoyl lactone to L-pantoic acid, was purified 2,400-fold to apparent homogeneity with a 1.96% overall recovery from Agrobacterium tumefaciens AKU 316 through a purification procedure including ammonium sulfate fractionation, and column chromatographies on DEAE-Sephacel, phenyl-Sepharose CL-4B, Sephacryl S-200, Mono-Q and alkyl-Superose. The relative molecular mass of the native enzyme estimated on high-pressure gel permeation chromatography was 62,000 Da, and the subunit molecular mass was estimated to 26,500 Da on SDS-polyacrylamide gel electrophoresis. The enzyme hydrolyzes several aromatic lactones, such as 3,4-dihydrocoumarin and homogentisic acid lactone, other than L-pantoyl lactone. The Km and Vmax for L-pantoyl lactone were 3.59 mM and 13.7micromol/min/mg, respectively. The enzymatic activity was inhibited by several chelating reagents, Fe2+, Sn2+, Pb2+, and Fe3+.

Agrobacterium tumefaciens↗
PubMed2000

Molecular cloning and overexpression of the gene encoding an NADPH-dependent carbonyl reductase from Candida magnoliae, involved in stereoselective reduction of ethyl 4-chloro-3-oxobutanoate.

An NADPH-dependent carbonyl reductase (S1) isolated from Candida magnoliae catalyzed the reduction of ethyl 4-chloro-3-oxobutanoate (COBE) to ethyl (S)-4-chloro-3-hydroxybutanoate (CHBE), with a 100% enantiomeric excess, which is a useful chiral building block for the synthesis of pharmaceuticals. The gene encoding the enzyme was cloned and sequenced. The S1 gene comprises 849 bp and encodes a polypeptide of 30,420 Da. The deduced amino acid sequence showed a high degree of similarity to those of the other members of the short-chain alcohol dehydrogenase superfamily. The S1 gene was overexpressed in Escherichia coli under the control of the lac promoter. The enzyme expressed in E. coli was purified to homogeneity and had the same catalytic properties as the enzyme from C. magnoliae did. An E. coli transformant reduced COBE to 125 g/l of (S)-CHBE, with an optical purity of 100% enantiomeric excess, in an organic solvent two-phase system.

Acetoacetates↗
PubMed2000

C19 odd-chain polyunsaturated fatty acids (PUfas) are metabolized to C21-PUfas in a rat liver cell line, and curcumin, gallic acid, and their related compounds inhibit their desaturation.

It was demonstrated that the rat liver cell line BRL-3A converted exogenous C19 odd chain-polyunsaturated fatty acids (PUFAs) into the corresponding C21- and C23-PUFAs as follows: 21:3n-8, 21:4n-8, 23:3n-8, and 23:4n-8 (from 19:3n-8); 21:4n-5, 21:5n-5, 23:4n-5, and 23:5n-5 (from 19:4n-5); 21:5n-2, 21:6n-2, 23:5n-2, and 23:6n-2 (from 19:5n-2). It presumed that these C19 PUFAs were converted through the mimic route to docosahexaenoic acid (22:6n-3) from eicosapentaenoic acid (20:5n-3). In addition, the characterization of the change of fatty acid composition of cellular lipids in rat liver cells were examined, using 19:4n-5 and several fatty acid desaturation inhibitors. Curcumin related compounds, curcumin, capsaicin, isoeugenol, 4-(4-hydroxy-3-methoxyphenyl)-3-buten-2-one, and gallic acid esters with near five carbon numbered alcohol had great changes of fatty acid composition of cellular lipids based on inhibition of the A6 desaturation of C24-PUFAs in rat liver cells.

Alkylation↗
PubMed2000

The inhibitory effect of interferon gamma and tumor necrosis factor alpha on intracellular multiplication of Neospora caninum in primary bovine brain cells.

Primary culture of bovine brain cells was examined for its susceptibility to Neospora caninum infections, and this model was used to investigate the effects of bovine interferon gamma (IFN-gamma) and tumor necrosis factors alpha (TNF-alpha) on tachyzoite growth. Tachyzoites of N. caninum grew well in this culture, and tachyzoite growth in astroglia and microglia were confirmed by immunocytochemical staining. IFN-gamma inhibited the tachyzoite growth, and this inhibition was not reversed by the addition of nitric oxide antagonist. TNF-alpha, to a lesser extent, also inhibited the tachyzoite growth. Th-1 type cytokines may play an important role in host defense mechanisms in N. caninum infection.

Animals↗
PubMed2000

Correlation between erythropoietin and lactate in humans during altitude exposure.

The plasma concentrations of both immunoreactive erythropoietin (EPO) and lactate were determined in four healthy untrained subjects at sea level and on the 2nd or 3rd day at altitudes (1,300 and 3,500 m). The mean plasma EPO (18.8 +/- 1.6 mU/ml at sea level) increased significantly on the 3rd day at 1,300 m (25.5 +/- 2.0 mU/ml, p < 0. 05) and showed an almost three-fold increase on the 2nd day at 3,500 m (53.5 +/- 3.7 mU/ml, p < 0.001). Likewise, the mean plasma lactate at 3,500 m (3.98 +/- 0.27 mmol/l) was 3.6 times as high as that at sea level (1.11 +/- 0.05 mmol/l) (p < 0.001). The plasma EPO concentrations were found to correlate well with the lactate concentrations at sea level and altitudes (r = 0.86, p < 0.01). These results are consistent with the well-known EPO/lactate response to altitudes and suggest that the circulating EPO concentration as well as blood lactate concentration can be used as an index of anaerobic condition.

Adult↗
PubMed2000

Solitary fibrous tumor arising from the falx cerebri--case report.

A 50-year-old female was admitted with headache and visual disturbance. Neuroimaging demonstrated a well-demarcated large tumor attached to the falx cerebri. The tumor was totally removed by surgery. Histological examination showed that the tumor consisted of spindle cells with no pattern in the collagenous background. Staghorn-like blood vessels were common. Immunohistochemical study showed the tumor cells were strongly positive for CD34 and vimentin, but negative for epithelial membrane antigen. The diagnosis was solitary fibrous tumor arising from the falx cerebri. Solitary fibrous tumor is rare within the cranial cavity, and can be distinguished from meningioma and hemangiopericytoma by the histological, ultrastructural, and immunohistochemical findings.

Brain Neoplasms↗
PubMed2000

Epidemiological study on food intake and Helicobacter pylori infection.

We conducted an epidemiological study to investigate the relation of food intake to Helicobacter pylori (H. pylori) infection in an area endemic for H. pylori. In this study, 365 subjects, 104 men and 261 women, were randomly selected from 7,389 adult (over age 20) inhabitants of town A, Japan. The prevalence of immunoglobulin G (IgG) class antibody to H. pylori (anti-H. pylori) was 83.7% and the prevalence of anti-H. pylori increased with age significantly (P < 0.05). Subjects with anamnesis of gastritis, gastroduodenal ulcer and gastric cancer tended to have a higher anti-H. pylori positive ratio (93.5%) than those without (81.0%). But there was no relationship between anti-H. pylori prevalence and sex, blood type, smoking or drinking habits. Daily intake of foods by food groups, nutrients and the concentrations of serum ingredients were compared between 37 anti-H. pylori-positive and 40 negative subjects selected from 365 inhabitants by matching up according to sex and age. The daily intake of cereals, potatoes and starches, and milks tended to be higher in positive than negative subjects, while the daily intake of algae and tea appeared to be a little higher in negative than in positive subjects. The daily zinc intake of antibody-positive subjects was significantly higher (P < 0.05) than in antibody negative subjects. On the other hand, the daily iron intake in negative subjects was significantly higher (P < 0.05) than in positive subjects. The serum concentrations of copper, zinc, and vitamin E tended to be higher in positive than negative subjects. But there were no significant differences in serum ingredients concentrations between antibody negative and positive subjects. Our findings suggest that iron and zinc intakes may effect on H. pylori infection.

Adult↗
PubMed2000

[Measurement of myocardial blood flow increase rate at exercise with 99mTc-tetrofosmin radionuclide angiography].

UNLABELLED: We developed new method to calculate myocardial blood flow increase rate at exercise (MBF-IR) with 99mTc-tetrofosmin (TF) radionuclide (RN) angiography and myocardial perfusion SPECT and assessed its feasibility using clinical data. METHOD: Fifteen patients who were suspected to have coronary artery disease underwent TF RN angiography and SPECT at exercise and at rest. Seven patients had coronary stenosis and eight patients had no significant coronary stenosis in coronary angiography. MBF-IRs were calculated by the following equation: [formula: see text] where Cr = regional myocardial count at rest, Ce = regional myocardial count at exercise [formula: see text] = the area under ventricular time activity curve at rest and [formula: see text] = the area under ventricular time activity curve at exercise. RESULT: Rate pressure product (RPP) was similar in patients with and without coronary stenosis (24,509 +/- 6701.9 vs. 27,196 +/- 4862.4, p = 0.39). MBF-IR was 1.88 +/- 0.73 in the area covered by stenosed coronary artery, 2.53 +/- 0.75 in unstenosed coronary artery in patients who have significant coronary stenosis and 2.97 +/- 0.77 in normal coronary patients. MBF-IRs in the area covered by stenosed coronary arteries were significantly smaller than that of normal coronary artery patient (p = 0.037). Interobserver and intraobserber reproducibility were good (r = 0.96, 0.95 respectively). There was strong positive correlation between MBF-IR and RPP in normal patients (r = 0.69, p = 0.0018), suggesting MBF increase depends on the cardiac workload. CONCLUSION: MBF-IR can be estimated by the combination of TF RN angiography and SPECT at exercise and at rest.

Aged↗